Preparation of formic esters.



pmTED STATES PATENT OFFICE.

ALBERT woLrF, or concerns, GERMANY, ASSIGNOR ro (Mas) MARIA s'rmnKnfio-EB,

NEnENeELsKIRcHEN, or COLOGNE-BICKENDQRF, GERMANY.

rn'nranarron or ronMI'o nsrnas.

No Drawing,

To all whom "it may concern:

Be it known that I, ALBERT WOLFE, a citizen of the German Em ire, and residing at Cologne-on-the-Rhine,-1'11 the Kingdom of Frussia and Empire of Germany, have invented certain new and useful Improvements in Preparation of Formi'c Esters, of which the following is a specification.

Esters of formic acid are as a rule prepared by treating formic acid with an alcohol in the presence of a water binding substance. I have found that such esters can be prepared from sodium formats the price of which. is much lower than that of formic acid.

It was Liebig who suggested a process for the preparation of ethylformate by distillinga mixture of sulfuric acid, ethyl alcohol and sodium 'formate (see Beilstem, Hand 790070 of Organic Gheme'stry, vol. 1, page 395) However, by that method the yield is less than 80% of the theory and besides the product is strongly acid.- My experiments have shown, that a formic ester of-neutral reaction can be obtained with a nearly theoretical yield, if a mixture of sodium formate, alcohol and sodium bisulfate be heated. The esters boiling below 100? C. can be separated by distillation at atmospheric. pressure,

whereas with esters boiling above 100 0.,

for example isoamyl formate, a. distillation under reduced pressure becomes necessary, because by a distillation at atmospheric pressure a decomposition sets in, if sodium bisulfate be present.

Example 1: 82 parts alcohol (1 11101.) are heated with 68 parts of pulverized sodium formate (1 mol.) and 240 parts of very finely powdered sodium bisulfate (2 mol.) in a closed vessel for about 10 hours up to a temperature of 80 C., the mass being stirred all the while. The mixture may also be slowly boiled in a bottle with a reflux cooler for about 10 hours whereupon the methyl formate may be distilled off. The ethyl formats is ob.a ned in a similar manner by heating 46 parts by weight of ethyl alcohol (1 mol.) with 68 v Specification of Letters Patent. Application filed June 25. 1912. Serial No. 705,683.

by weight of methyl Patented Oct. 1,1912.

parts sodium formats (1 mol.) and 240 parts sodium bisulfate (2 mol.)

Example 2: 88 parts by weight of isoamyl alcohol are heated with 68 parts of sodium formate and 240 parts of sodium bisulfate for 10 hoursup to 100 C.', the mass'being agitated all the while. The mass is allowed to cool down to 50 C. and theLamyl formats formed is distilled oil at 50 C. and under a reduced pressure of 40 to mm. The product of reaction'is allowed to cool down to common tern eratures, whereupon the ester formed is ecanted from the crystals that have separated out and the ester is purlfied by distillation. Crude fusel oil can be converted into an ester in an analogous manner'. p What I claim is: o

1. The hereindescribed process of pro? ducing formic Jesters, consisting in heating a mixture of an alcohol, sodium formate and sodium bisulfate, and thereafter distill-' ing off the resultingester.

2. The herein described process of "producing formic esters, consisting inadmixing a suitable quantity of an alcohol with 68- parts of sodium formats and 240 parts ducing formic esters, consisting in admixor sodium bisu' lf'ate, heating the mixture,

in}; 88 parts. by weight of isoamyl alcohol,f

68parts of sodium formats and 240 parts of sodiumbisulfate, heating the mixture for approximately ten hours to a temperature of approximately 100 degrees (3., cooling the mixture down to approximately 50 degrees (1, distilling-off the resulting amyl formate at the temperature last mentioned under a pressure of. from 40 to 50 mm., and finally removing and purifying the ester.-

In testimony whereof I affix my signature in presence of two witnesses.

ALBERT WOLFF.

Witnesses: f"

Louis fVANnonr,

BESSIE F. DUNLAP. 

